It has been appreciated for some time that Alzheimer's Disease has a complex etiology. At least 15 percent of the cases appear to be due to the inheritance of an autosomal-dominant mutation, but the majority are "sporadic", showing no clear association with any identifiable genetic or environmental factor. Feldman, R. G., et al., Neurology, 13:811-824 1963; Heston, L. L., et al., Arch Gen. Psychiat., 38:1084-1090 (1981); Terry, R. D., Aging, 7:11-14 (1978); Jarvik, L. F. and Matsuyama, S. S., "The Biological Substrates of Alzheimer's Disease", Academic Press, pp. 17-20 (1986). Even identical twins can show a large discordance in the age of onset of the disease. Nee, L. E., et al., Neurology, 37:359-363 (1987). Yet despite this variation, Alzheimer's Disease shows a uniform set of clinical and pathological features--progressive loss of memory and other intellectual functions beginning in middle to late life, coupled with neuronal cell loss in the higher centers of the brain. Price, D. L., Ann. Rev. Neurosci., 9:489-512 (1986).
While much has been learned about the biochemistry and expression of the aberrant protein deposits that characterize Alzheimer's Disease, progress toward the development of methods for the diagnosis and treatment of the disease has been slow. This is due, at least in part, to the fact that the molecular basis for the disease pathology has remained obscure.